DIY Bodywork/Paint on 944 Galvanized Panels
11-14-2018, 06:44 PM
#1
Burning Brakes
Thread Starter
DIY Bodywork/Paint on 944 Galvanized Panels
I have a fender and a front turbo bumper to repair and paint and I'm having trouble finding information dealing with this, especially when it comes to galvanized metal. Anyone out there with body shop experience or refinishing of Porsche panels?
I've read that galvanized metal requires an etching before painting, usually using simple vinegar but this information is usually in reference to non auto applications so I don't know whether this is accurate or not.
Basically I have a fender which has small amounts of cracked bondo and other small damage which requires sanding down to bare metal, mostly only with 1 inch diameter or smaller of bare metal. Also, the fender was repainted from red to black. I will be needing a black final color. The paint is decent except for the areas that are damaged so not sure that it requires a full repaint or just blending of the new paint. And, again, the color is black L041 so keep that in mind when it comes to blending as I'm guessing that makes things much easier.
And you are correct in assuming I have very little experience in bodywork. However, i did paint a car many years ago and still remember the amount of work and pretty sketchy results that came from it all. And yet, I still want to do this myself. I plan on a 2 stage paint with basecoat and clear coat. I don't know whether enamel or lacquer is the best choice. I've read that enamel is the way to go and that means a water base and yet whenever I look for paint, it's mineral based.
Are there any online painting tutorials or instructional videos? There really doesn't seem to be very much info at all online which is strange.
Many thanks and please don't tell me to take it somewhere and have the work done, I'm short on money and have nothing but time right now. Plus, I want to learn as this is the final part of auto work I have trouble with or can't do. I know in the end, I won't even save that much money but i'd still rather do it myself.
I've read that galvanized metal requires an etching before painting, usually using simple vinegar but this information is usually in reference to non auto applications so I don't know whether this is accurate or not.
Basically I have a fender which has small amounts of cracked bondo and other small damage which requires sanding down to bare metal, mostly only with 1 inch diameter or smaller of bare metal. Also, the fender was repainted from red to black. I will be needing a black final color. The paint is decent except for the areas that are damaged so not sure that it requires a full repaint or just blending of the new paint. And, again, the color is black L041 so keep that in mind when it comes to blending as I'm guessing that makes things much easier.
And you are correct in assuming I have very little experience in bodywork. However, i did paint a car many years ago and still remember the amount of work and pretty sketchy results that came from it all. And yet, I still want to do this myself. I plan on a 2 stage paint with basecoat and clear coat. I don't know whether enamel or lacquer is the best choice. I've read that enamel is the way to go and that means a water base and yet whenever I look for paint, it's mineral based.
Are there any online painting tutorials or instructional videos? There really doesn't seem to be very much info at all online which is strange.
Many thanks and please don't tell me to take it somewhere and have the work done, I'm short on money and have nothing but time right now. Plus, I want to learn as this is the final part of auto work I have trouble with or can't do. I know in the end, I won't even save that much money but i'd still rather do it myself.
11-14-2018, 08:45 PM
#2
Race Car
I can answer direct questions as to what to do but you seem too unsure at this stage.
Enamel (or urethane- a better product) are catalyzed by a hardener.
Only way it is only water based is if local laws only allow this type of paint products and to the best of my knowledge, Tennessee is not such a state but California may be.
Personally, I'd take the fender down to the factory primer/sealer, some red showing is ok (the factory finish) since you don't know the quality of prep the person who sprayed it black used.
Gonna be pretty labor intensive by hand if you don't have a 6" random orbital sander but there are cheap ones out there.
Most of a bumper cover will have to be sanded by hand.
Going down to bare metal is no problem.
You have two choices, either acid etching primer or epoxy primer for bare metal.
What's a rough idea as to what you think you want to spend in supplies and I'll point you in the right direction for products.
T
Enamel (or urethane- a better product) are catalyzed by a hardener.
Only way it is only water based is if local laws only allow this type of paint products and to the best of my knowledge, Tennessee is not such a state but California may be.
Personally, I'd take the fender down to the factory primer/sealer, some red showing is ok (the factory finish) since you don't know the quality of prep the person who sprayed it black used.
Gonna be pretty labor intensive by hand if you don't have a 6" random orbital sander but there are cheap ones out there.
Most of a bumper cover will have to be sanded by hand.
Going down to bare metal is no problem.
You have two choices, either acid etching primer or epoxy primer for bare metal.
What's a rough idea as to what you think you want to spend in supplies and I'll point you in the right direction for products.
T
11-14-2018, 08:57 PM
#3
As I am in a very similar situation, I'll pass what I've learned (so far.) Acrylic Urethane is going to be the most common 2 stage paint available. Not all Urethane paints will be water based. (Your sig says LA, so you may not have access.) Your best bet is going to be to visit a local automotive paint supplier. There are some good options online as well. In any event, whichever paint you choose will have a data sheet that defines what the proper preparation is for your surface. What I've come across for dealing with bare metal is Epoxy primer, followed by a high build primer, then base coat, followed by clear coat. For dealing with my '84 (L041), I have decided to use a Urethane Single stage.
Hope this info helps.
James
Hope this info helps.
James
11-15-2018, 02:53 PM
#4
Race Car
agree with what's already been said. don't do spot repairs on a fender - paint the whole thing; blending is pretty tough.
Eastwood has a lot of great self help videos.
Eastwood has a lot of great self help videos.
11-15-2018, 05:21 PM
#5
Rennlist Member
Here are a couple of tutorials I've written on paint. The first one is the first class expensive way. The second one is not!
https://newhillgarage.com/2016/11/29...ack-car-paint/
https://newhillgarage.com/2016/02/07...r-9-paint-job/
You admit you have a lot to learn. The great thing about paint is if you don't like the results, you can always try again. A couple of comments. Enamel paint is never catalyzed. It is an air dry paint. There are modern urethane paints that are water based, although many are still solvent based. The water based paints are formulated to minimize volatile solvents and thus are mandated in areas with poor air quality. Like CA. The $8 Rustoleum paint is an oil based air dry paint. As far as I know, solid colors on mid 80's Porsches were "single stage", not basecoat/clearcoat. They probably used an early version of urethane. As someone pointed out, Eastwood is very helpful and friendly to DIY folks. And I think they will sell small quantities of catalyzed urethane paints. That said, there are a lot of shades of "black" so it would be best to do an entire piece, such as the bumper, to avoid direct color matching issues. Regardless, new paint will always be shinier than 40 year old paint. You may actually wind up knocking down the gloss, using rubbing compounds, on any new paint you apply to get a good match! It's a dilemma and why it is hard to get a shop to deal with older cars.
Good luck!
https://newhillgarage.com/2016/11/29...ack-car-paint/
https://newhillgarage.com/2016/02/07...r-9-paint-job/
You admit you have a lot to learn. The great thing about paint is if you don't like the results, you can always try again. A couple of comments. Enamel paint is never catalyzed. It is an air dry paint. There are modern urethane paints that are water based, although many are still solvent based. The water based paints are formulated to minimize volatile solvents and thus are mandated in areas with poor air quality. Like CA. The $8 Rustoleum paint is an oil based air dry paint. As far as I know, solid colors on mid 80's Porsches were "single stage", not basecoat/clearcoat. They probably used an early version of urethane. As someone pointed out, Eastwood is very helpful and friendly to DIY folks. And I think they will sell small quantities of catalyzed urethane paints. That said, there are a lot of shades of "black" so it would be best to do an entire piece, such as the bumper, to avoid direct color matching issues. Regardless, new paint will always be shinier than 40 year old paint. You may actually wind up knocking down the gloss, using rubbing compounds, on any new paint you apply to get a good match! It's a dilemma and why it is hard to get a shop to deal with older cars.
Good luck!
11-17-2018, 03:54 PM
#6
Burning Brakes
Thread Starter
Here are a couple of tutorials I've written on paint. The first one is the first class expensive way. The second one is not!
https://newhillgarage.com/2016/11/29...ack-car-paint/
https://newhillgarage.com/2016/02/07...r-9-paint-job/
You admit you have a lot to learn. The great thing about paint is if you don't like the results, you can always try again. A couple of comments. Enamel paint is never catalyzed. It is an air dry paint. There are modern urethane paints that are water based, although many are still solvent based. The water based paints are formulated to minimize volatile solvents and thus are mandated in areas with poor air quality. Like CA. The $8 Rustoleum paint is an oil based air dry paint. As far as I know, solid colors on mid 80's Porsches were "single stage", not basecoat/clearcoat. They probably used an early version of urethane. As someone pointed out, Eastwood is very helpful and friendly to DIY folks. And I think they will sell small quantities of catalyzed urethane paints. That said, there are a lot of shades of "black" so it would be best to do an entire piece, such as the bumper, to avoid direct color matching issues. Regardless, new paint will always be shinier than 40 year old paint. You may actually wind up knocking down the gloss, using rubbing compounds, on any new paint you apply to get a good match! It's a dilemma and why it is hard to get a shop to deal with older cars.
Good luck!
https://newhillgarage.com/2016/11/29...ack-car-paint/
https://newhillgarage.com/2016/02/07...r-9-paint-job/
You admit you have a lot to learn. The great thing about paint is if you don't like the results, you can always try again. A couple of comments. Enamel paint is never catalyzed. It is an air dry paint. There are modern urethane paints that are water based, although many are still solvent based. The water based paints are formulated to minimize volatile solvents and thus are mandated in areas with poor air quality. Like CA. The $8 Rustoleum paint is an oil based air dry paint. As far as I know, solid colors on mid 80's Porsches were "single stage", not basecoat/clearcoat. They probably used an early version of urethane. As someone pointed out, Eastwood is very helpful and friendly to DIY folks. And I think they will sell small quantities of catalyzed urethane paints. That said, there are a lot of shades of "black" so it would be best to do an entire piece, such as the bumper, to avoid direct color matching issues. Regardless, new paint will always be shinier than 40 year old paint. You may actually wind up knocking down the gloss, using rubbing compounds, on any new paint you apply to get a good match! It's a dilemma and why it is hard to get a shop to deal with older cars.
Good luck!
One thing I've now become worried about are the health issues and respirators. Do all paints have isocynates or is that just some urethanes? What air apparatus did you use and how much are they? The masks are cheap enough but pretty sketchy if used for isocynates. I'd just rather use a paint without isocynates but not sure if that's a realistic option.
And now for the stupid question of the day: On Wheeler Dealers they often use a rattlecan spray paint for fairly major touch ups or complete panels. Is this a bad decision? I always thought for serious paint you must use a gun/compressor. I've also seen the Preval sprayer which allows you to buy any paint and use their propellant to spray. They're disposable and cheap as well as easy to find. I've read really good reviews and bad; it seems to be related to the paint viscosity. Just looking at all the options. And not sure if the rattlecan bias is due to the paint in the can (not as durable) or the way it's applied (spray nozzle; mixture.)
It sure is complicated and expensive. Maybe body shops aren't such a giant rip off....
11-17-2018, 06:37 PM
#7
Rennlist Member
I'm glad you asked about the health issues. All urethane paints contain isocyanates, to my knowledge. I don' think it's a "one whiff and your dead" scenario but it is a serious concern. Early on I purchased a supplied air system, which is a long hose that pulls clean air in from outside my paint booth with me wearing a hood. It was not cheap but when I wear it, I don't get a hint of paint fumes. A property fitted mask with organic filters will suffice but getting a good fit can be a problem. Facial hair is a no-no.
You might be very happy using the Duplicolor or Rustoleum line of rattle can paints. They are not catalyzed so are typically enamals or acrylic-laquers, I think. There is minimal health risks. I have used them with good results.
The biggest advantage of the urethanes for me, as a DIYer, is that they can be sanded after the paint drys, to deal with blems, runs, etc. But the steps for doing this also involve a lot of material costs, as discussed in my article. And no, I don't think a spray gun gives you a dramatically better paint job. It just is the best solution when you are painting large areas or doing a lot of production work.
Rereading your original post, if you are willing to stick with black, I have had good luck with Rustoleum Satin Black. It is pretty forgiving. On my track car, I paint the air dam black just because it is going to get peppered with black tire debris so why not. Regarding your original question about the galvanizing, I think the Rustoleum or Duplicolor primers will stick just fine. Try and stick with a single mfg line of primer and top coat, ie. use Duplicolors range of products or use Rustoleums range of products. Don' mix and match.
You might be very happy using the Duplicolor or Rustoleum line of rattle can paints. They are not catalyzed so are typically enamals or acrylic-laquers, I think. There is minimal health risks. I have used them with good results.
The biggest advantage of the urethanes for me, as a DIYer, is that they can be sanded after the paint drys, to deal with blems, runs, etc. But the steps for doing this also involve a lot of material costs, as discussed in my article. And no, I don't think a spray gun gives you a dramatically better paint job. It just is the best solution when you are painting large areas or doing a lot of production work.
Rereading your original post, if you are willing to stick with black, I have had good luck with Rustoleum Satin Black. It is pretty forgiving. On my track car, I paint the air dam black just because it is going to get peppered with black tire debris so why not. Regarding your original question about the galvanizing, I think the Rustoleum or Duplicolor primers will stick just fine. Try and stick with a single mfg line of primer and top coat, ie. use Duplicolors range of products or use Rustoleums range of products. Don' mix and match.
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11-17-2018, 06:43 PM
#8
Rennlist Member
Wurth also has a good reputation for rattle can products.
11-18-2018, 12:28 PM
#9
Race Car
I’ve used Eastwood’s rattle can catalyze 2k urethane paint with really nice results. It sprays very fine and gives a nice finish which, so far, seems more durable than off the shelf rattle can paint
11-18-2018, 12:39 PM
#10
Race Car
A spray gun doesn't give you a dramatically better paint job...?
A spray gun, even a cheap one, has infinite control of pressure, spray fan, material quantity and atomization control adjustability.
You can hold a spray gun in one position (ex - an edge or border) and control material to the point of airbushing until a complete coat is achieved.
A single stage enamel or urethane mixed in a cup of varying components will be 10 x more durable against scratches, contact with volatile fluids (gasoline, oil, etc) than ANY paint product from a spray can.
T
A spray gun, even a cheap one, has infinite control of pressure, spray fan, material quantity and atomization control adjustability.
You can hold a spray gun in one position (ex - an edge or border) and control material to the point of airbushing until a complete coat is achieved.
A single stage enamel or urethane mixed in a cup of varying components will be 10 x more durable against scratches, contact with volatile fluids (gasoline, oil, etc) than ANY paint product from a spray can.
T
11-18-2018, 02:07 PM
#11
Rennlist Member
T, everything you say is true. But the cost of entry to properly spray urethane (equipment and materials) is quite steep. I'm just trying to say rattle can paint jobs can be made to look quite presentable. I wouldn't rule it out if I was on a tight budget.
11-18-2018, 04:46 PM
#12
Race Car
I have had great success with LimCo under the BASF product line, same company that own RM and Glasurit.
Although the black is fairly translucent for a SS urethane (will take 3 coats), a pint will give you almost a qt of sprayable material at 4:2:1
A pint of Gloss Black Super Urethane costs me about $22
A 1 qt can of reducer (goes a long way) is $10-15
And you can buy the hardener in a quantity as little as 1/2 pint can.
Another + about mixable, gun sprayable material that I never mentioned is that you can buy hardener is LHS/LHM/LHF, Limco Hardener Slow, Medium and Fast as well as multiple temperature ranges of reducers to fine tune your sprayable material for room/atmosphere conditions as well as dry time, something you are stuck with using a spray can.
Most people can have access to borrow a compressor large enough to paint a fender and an HVLP gun good enough to get a pretty decent finish can be had for less than $100.
I have a large number of buddies in auto/body business and they all swear by Iwata and Sata ($400-$600 range) Jet but I probably use, a Sharpe/Finex 2000, C.A. Technologies Techline and 3M Accuspray to do 90% of everything I do....., none of which are bank account breaking guns. I have used pretty much every gun made and while I love the 2/3 I mentioned above, the plastic 3M Accuspray with reusable nozzles and PPS for the entry price is pretty hard to beat.
Painting these couple pieces the OP mentioned doesn't have to break the bank, even using some pretty darned good products and equipment.
T
11-18-2018, 05:08 PM
#13
One quick point on the rattle can vs 2k (Urethane) paints. Both "can" give acceptable results. (I've found that a spray gun gives a better finish, IMO.) Catalyzed urethane will last much longer than others, due to the chemical hardness. Which ever way you go, don't start with rattle can and decide half way to switch to Urethane! The solvents (activators / reducers) have a nasty habit of reacting badly with rattle can spray paint! Which typically means sanding everything off and starting over. There are 2k Urethane rattle cans available. From what I've seen, it's a punch the pin to initiate the activator mix. Afterwards, you have an hour or two to use the can. Then it's toast.
From the health standpoint, yes, a respirator with the correct filters / cartridges is the lowest acceptable protection in my book. Dust masks are worthless. Don't forget your eyes too. If you can breathe it in, it can settle in your eyes as well.
Equipment is the next biggest hurdle. I've shot replacement plastic bumpers for my 528i with a Husky gun. (I think the std / HVLP set cost me about $90.) I also picked up a 13gal 5HP compressor at a local pawn show for $75. Hoses and fittings were another $40. You will want a in-line water separator if you plan on spraying paint!
Not trying to scare you away from spraying Urethane, but I've learned some lessons the hard way in the past. I'd rather you don't have too as well.
James
From the health standpoint, yes, a respirator with the correct filters / cartridges is the lowest acceptable protection in my book. Dust masks are worthless. Don't forget your eyes too. If you can breathe it in, it can settle in your eyes as well.
Equipment is the next biggest hurdle. I've shot replacement plastic bumpers for my 528i with a Husky gun. (I think the std / HVLP set cost me about $90.) I also picked up a 13gal 5HP compressor at a local pawn show for $75. Hoses and fittings were another $40. You will want a in-line water separator if you plan on spraying paint!
Not trying to scare you away from spraying Urethane, but I've learned some lessons the hard way in the past. I'd rather you don't have too as well.
James
11-18-2018, 06:52 PM
#14
Race Car
I use these.
One screwed right onto the gun.
Disposable Compressed Air Spray Gun Filter
T
One screwed right onto the gun.
Disposable Compressed Air Spray Gun Filter
- For use with high volume, low pressure (HVLP) spray guns using shop air.
- Designed to remove the smallest contaminant particle, oil-aerosol or drop of moisture to supply clean, dry, oil free air to your spray gun.
T
11-28-2018, 07:19 PM
#15
Burning Brakes
Thread Starter
Hey everyone, thanks so much for the tips, I appreciate all of it!
I've been watching a lot of Eastwood videos about paint and body work. I've learned a lot and I've removed a bunch of bad bondo that was cracked and even tapped the metal into better shape. It's quite a zen process! And i can see the metal taking shape and smoothing out. One of the most important tips i learned from the videos was to smooth out the metal as much as possible so you never need more than 1/8" of bondo to make it smooth. The other important thing I learned was about using a guide coat to reveal lower points when sanding.
Lots more to learn though and lots more to buy! No way this will be cheaper than a body shop but I'm learning and I can pay a little at a time. Plus, it is probably difficult to find a body shop willing to do a single fender.
The health concerns are a bit scary though. Is there a decent paint that doesn't have isocyanates? Even if I'm giving up a bit of quality, I'd rather outlive the paint on my fender! From what I've read, if you've smelled the paint when using isocyanates, it's too late. Most of the issues I've read with an isocyanate paint have to do with developing an increased sensitivity to isocyanates and then even a small amount can trigger severe asthma attacks.
I've been watching a lot of Eastwood videos about paint and body work. I've learned a lot and I've removed a bunch of bad bondo that was cracked and even tapped the metal into better shape. It's quite a zen process! And i can see the metal taking shape and smoothing out. One of the most important tips i learned from the videos was to smooth out the metal as much as possible so you never need more than 1/8" of bondo to make it smooth. The other important thing I learned was about using a guide coat to reveal lower points when sanding.
Lots more to learn though and lots more to buy! No way this will be cheaper than a body shop but I'm learning and I can pay a little at a time. Plus, it is probably difficult to find a body shop willing to do a single fender.
The health concerns are a bit scary though. Is there a decent paint that doesn't have isocyanates? Even if I'm giving up a bit of quality, I'd rather outlive the paint on my fender! From what I've read, if you've smelled the paint when using isocyanates, it's too late. Most of the issues I've read with an isocyanate paint have to do with developing an increased sensitivity to isocyanates and then even a small amount can trigger severe asthma attacks.